Production of alcohol free from fusel oil



Patented Dec. 4, 1934 PRODUCTION OF ALCOHOL FREE FROM FUSEL OIL Adolf Gorhan, Liesing, near Vienna, Austria, assignor to Deutsclie Goldand Silber Scheideanstalt vormals Roessler, Frankfort-on-the- Main, Germany, a company of Germany No Drawing. Application June 15, 1932, Serial No. 617,473. In Germany June 19, 1931 14 Claims. ((1202-67) This invention relates to the production of alcohol free from fusel oil. in order to remove the fusel oil from crude spirit, almost all the known methods of operation make use of the fact that by a process of rectification by means of ordinary rectifying apparatus a distillate that is entirely free from fusel ,oilcanbe obtained if the vapours are concentrated to such an extent that, after condensation, theyt-contain 94.5 to 95 per cent by weight of spirit (compare Foth, Handbuch der Spiritusfabrikation, 1929, page 731, fourth paragraph). In the case of known processes and by ordinary rectiflcatlon this concentration is attained only by theconsumption of considerable quantities of steam and cooling water whereas by the present invention it is possible to carry out, with a considerably reduced consumption of steam and cooling water, a direct removal of the fusel oil from -aqueous alcohol containing, for example, 80 to 90 per cent by weight of alcohol.

The essence of the present invention resides in the employment of suitable salts or mixtures of salts in the carrying out of the process of fusel oil removal. The vapour phase of aqueous alcohol containing fusel oil has in the presence of suitable substances, especially salts such as alkali or earth alkali salts of the fatty acids, 9. higher concentration of alcohol than in the absence of these salts. Since the content of fusel oil in alcohol is essentially occasioned by the fact that,

together with the alcohol vapour, a considerable amount of water vapour passes into the vapour phase, theaddition of the substances mentioned causes the quantity of water vapour in thevapour phase to be reduced to such an extent that all the fusel oils remainbehind, without it being necessary, as in the case of the ordinary rectification, to employ tall columns and/or to work with large reflux apparatus and a correspondingly high consumption of steam.

The process can be carried out for example by running into a distilling vessel one of the substances that have been defined above'with regard i to their function-e. g., a mixture of potassium acetate and sodium acetate-and then running in the alcohol to be purified. The vapours are passed through a simple rectifying column which is worked with a relatively small reflux attachment. Alternatively the alcohol vapour containing the fusel oil, such as is obtained by vaporization or as occurs in the concentration of mashes, may be passed. through one or more vessels charged with a suitable salt solution or suspen- 21 sion, whereupon the vapours also pass through a short column; in such a way alcohol that is entirely free from fusel oil is obtained with quite small consumption of steam and cooling water. The action of such an arrangement can be substantially improved by causing suitable'solutions 50 or suspensions of appropriate salts to flow actually in a column in counter-current to the vapours; by suitably dimensioning the columnandthe quantities of salts, the purifying operation can be performed entirely with the aid"of this simple device-e. g. a suitable washing column filled with Raschig rings. Furthermore, this purin cation can be utilized for bringing the alcohol simultaneously to a higher concentration than is necessary for merely removing the fusel oil in accordance with the foregoing description; for example, by treatment with a solution or suspension of the almost anhydrous salts- -e. g..of a mixture of potassium acetate and sodium acetate in absolute alcohol-an alcohol of at least 99.8% 7 by weight and at the same time entirely free from fusel oils is directly obtained.

Example I A mixture of 1'75 parts of potassium acetate and 75 parts of sodium acetate, 150 to 200 parts of water and 50 parts of ethyl alcohol are placed in a distilling vessel and alcohol containing fusel oil is run in. The distilling vessel is provided with a short column. The distillation gives an alcohol of about 95% by weight that is free from fusel oil. Towards the end of the operation, the alcohol contained in the still can even be, distilled of! until the quantity of fusel oil in the stillamounts toabout 40% of the alcohol that is still present, without any products containing fusel oil reaching the distillate.

Example II For the purpose of carrying out the separation of the fusel oil in the manner described in Example I entirely continuously, the mixture in the still must be drawn off continuously or discontinuously in separate fractions and be freed from the concentrated fusel oil and water.- For driven off can, owing to the great-concentration of fusel oil in the contents of the still that is occasioned by the process, and consequently in relation to the alcohol, be very readily worked up into fusel oil and an alcohol which is poor in fusel oil and which is returned into the process.

Example III anhydrous. The working up of the salt solution in this case is effected by completely removing the residual water from the mixture of salts after driving ofl alcohol and fusel oil and dissolving the molten salt mixture, that is left, in absolute alcohol in this condition and again supplying it 1 to the dehydrating column.

What I claim is:-

1. A process of producing ethyl alcohol of greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous alcoholic solution containing fusel oil and at least 10% water with an absolute alcoholic solution of a dehydrating fatty acid salt, drawing oil and condensing the alcohol vapors free from fusel oil and retaining the fusel oil with the vapors free from fusel oil and retaining the fusel salt solution.

2. A process of producing ethyl alcohol 01 ,greater than 95% concentration free from fusel oil comprising contacting the vapor of an aque+ ousalcoholic solution containing fusel oil and at least 10% water with: a water-free solution inert to alcohol and fusel oil of a dehydrating fatty acid salt, drawing ofl and condensing the alcohol vapors free from fusel oil and retaining the fusel oil with the salt solution.

3-. A process of producing ethyl alcohol 0;!

greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous alcoholic solution containing fusel oil and at least 10% water with an absolute alcoholic solution of a mixture of alkali acetates, drawing of! and condensing the alcohol vapors free from fusel oil and retaining the fusel oil with the, salt solution.

4. A process of producing ethyl alcohol of greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous alcoholic solution containing i'usel oil and at least 10% water with an absolute alcoholic solution of potassiumand sodium acetate, drawing of! and condensing the alcohol vapors free from fusel oil and retaining the fusel oil with the salt solution.

5. A process of producing ethyl alcohol of greater than 95% concentration free from fusel. -oil comprising contacting the vapor of an aqueous alcoholic solution containing fusel oil and at least 10% water with a solution containing about 70% potassium acetate and about 30% sodium acetate, drawing off and condensing the alcohol oil with the salt solution.

6. A .process of producing ethyl alcohol of greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous-alcoholic solution containing fusel oil and at least 10% water with an absolute alcoholic solu- I 1,982,988 mixture of alcohol, fusel oil and water that is tion containing about 70% potassium acetate and about 30 sodium acetate, drawing oil and condensing the alcohol vapors free from fusel oil and retaining the fusel oil with the salt solution.

7. A process of producing ethyl alcohol of greater than 95% concentration free from fusel oil comprising distilling the crude spirit whereby an aqueous alcoholic solution containing fusel oil and at least 10% water in the vapor phase is obtained, then contacting the vapors with an absolute alcoholic solution of a dehydrating fatty acid salt, drawing ofi and condensing the alcoholic vapors free from fusel oil and retaining the fusel oil with the salt solution.

'8. A process of producing ethyl alcohol of greater than 95% concentration free from fusel oil comprising distilling the crude spirit whereby the vapor or an aqueous alcoholic solution containingfusel oil and at least 10% water is obtained, then subjecting the vapor in countercurrent flow to the action of an absolute alcoholic solution of a dehydrating fatty acid salt, drawing off and condensing the alcohol vapor free from fusel oil and retaining the fusel oil with the salt solution.

9. A process of producing ethyl alcohol of greater than concentration free from fusel oil comprising distilling the crude spirit whereby the vapor of an aqueous alcoholic solution containing fusel oil and at least 10% water is obtained, then subjecting the vapor in countercurrent flow to the action of an absolute alcoholic solution of anhydrous alkali acetates, drawing oil and condensing the alcohol vapor free from fusel oil and retaining the fusel oil with the salt solution.

10. A process of producing ethyl alcohol continuously of greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous alcohol solution containing fusel oil with an absolute alcoholic solution of dehydrating fatty acid salt, drawing oil and condensing the alcohol vapors free from the fusel oil, removing the fusel oil together with the salt solution and small quantities of alcohol, removing from this mixture the fusel oil and alcohol, separating oil the fusel oil from the alcohol, dehydrating the residual salt solution in a molten state and dissolving the dehydrated salt in the same molten state in absolute alcohol for reuse as contact materiaL.

11. A process of producing ethyl alcohol con tinuously of greater than 95% concentration free from fusel oil comprising contacting the vaporof an aqueous alcohol solution containing fuseloil with an absolute alcoholic solution of dehydrating fatty acid salt, drawing of! and condensing. the alcohol vapors free from the fusel oil, removing the fusel oil together with the salt solution, separating the fusel oil from the salt solution, dehydrating the residual salt solutionand dissolving the same inabsolute alcohol for reuse in the process.

12. A process of producing ethyl alcohol continuously of greater than 95% concentration free from fusel oil comprising contacting the vapor of an aqueous alcohol solution containing fusel oil with a water-free. solution inert to alcohol and fuseloil of alkali acetates, drawing off and condensingthe alcohol vapors free from the fusel oil, removingthe fusel oil together with the acetate solution, separating the fusel oil from the residual acetate solution, dehydrating the acetate tinuously of greater than 95% drom tusel oil comprising contacting the vapor 0!- rin the iusel oil I solution and the contain a solvem'm reuse in the process.

18. A process of producing ethyl alcohol con-'- concentration iree aqueous alcohol solution containing iusel oil with an absolute alcoholic solution or potassium and sodium acetates, drawing oil and condensing the alcohol vapors tree from the iusel oil, removtogether with the salt solution and small quantities of alcohol, removing from this mixture the iuseloil and alcohol,- separating 03 the iusel oil from the alcohohreturning the alcohol separated from the fuse! oil tothe contacting step, dehydrating the salt solution in a molten state and dissolving the dehvdrsted salt solution in the molten state in absolute alcohol for reuse in the process.

i4.-A process otproduoingethyl'aleohol con-.w

tinuously of greater than tree from iusel oil vapor of aqueous iusel oil with an drawing oi! and condensing thealcohol-vapors:

tree irom the iusel oil, removing the iusel 'oii together with the salt solution and small quantities 0! alcohol, removing from this mixture the iusel oil and alcohol. separating oi: the inset oil from the alcohol, returning the alcohol separated irom the iusel oil to the contacting step-.

dehydrating the salt solution in a molten'stateand (8801M the dehydrated salt solution in the;

molten state in absolute alcohol ior reuse in' the' 

